It has been estimated that 2–3% of all hospital admissions in Australia are medication-related and 50% are preventable (1, 2). A recent review of data from 44 general medical practices in New Zealand demonstrated that 10.8% of patients experienced medication-related harms over a 3-year period. Most were deemed minor; however, one in five harms were moderate or severe and three patients died due to medication harm (3). The almost 2 million Australians that suffer an adverse event from medicines each year (4) are not all due to an adverse drug reactions (ADR), but are also caused by human and systemic medication errors (Table 3.1). Patients claiming a history of drug allergy are a daily occurrence in dental practice, so this chapter includes a description of allergy physiology, various adverse reactions due to drugs, with detail regarding immune-mediated allergic reactions, focussing on Type 1 and 4 reactions. As many claimed allergic reactions by patients are false, how to correctly diagnose and manage actual drug allergies will also be discussed.

A hallmark of the 21st century is that people are living longer than ever before, making it increasingly likely that dental patients are in their later years. In 2020, the proportion of Australians aged 65 years and older reached 16.3%, increasing from 12.4% in 2000, and it is currently predicted to reach ~25% by 2050. Meanwhile, people aged 85 years and over are in the fastest growing sector, increasing by 2.5% in 2020 alone, and by 110% over the preceding 20 years, compared with growth of only 35% for the total population over the same period. Caring for older patients with ageing oral health is an increasing challenge for dental practitioners. In addition to living longer, older Australians are retaining their own teeth for longer. Changes in the oral cavity due to ageing reflect changes throughout the rest of the body, such as loss of elasticity, decreased muscle tone and degradation of hard and soft tissues due to wear and tear. With greater likelihood of medical diagnoses and prescription of medications, healthcare of older patients becomes more complex. Many age-related changes in physiology alter the pharmacokinetics and pharmacodynamics of medicines in older people.

Dentists are permitted to obtain, supply, possess, administer, and prescribe medicines for the management of their patients’ oral health. In Australia, dental prescribing and provision of medicines are regulated by individual state and territory drug legislation, as well as through national rules and regulation through the Dental Board of Australia, the Pharmaceutical Benefits Scheme (PBS) and Therapeutic Goods Administration (TGA). In Aotearoa New Zealand, subsidisation of medicines is determined through the Pharmaceutical Management Agency (PHARMAC) and categorisation of medicines and legalities around their availability is determined by the Medicines Act 1981, with listing of approved medicines on the Pharmaceutical Schedule.

An adverse drug reaction (ADR) is defined as a response to a medicine that is noxious and unintended, and occurs at doses normally used or tested in humans’ (1). ADRs that manifest in the orofacial region are common, being associated with at least 43 of the top 100 drugs dispensed on the Pharmaceutical Benefits Scheme (PBS) in Australia (2). ADRs are becoming more relevant in dentistry with increasing awareness of oral ADRs amongst dental professionals, increasing number of people taking medications, polypharmacy becoming more common especially with increasing age, and the elderly being more prone to adverse effects. In Australia, 87.1% of the population aged 50 years or more takes at least one medicine regularly (3). ADRs are a major public health problem because they occur frequently and contribute significantly to human suffering and economic expense. The Medication Safety Report from the Pharmaceutical Society of Australia in 2019 stated that 250,000 Australian hospitalisations per year are caused by adverse drug events, most of which are due to ADRs, at a cost of approximately AU$1.4 billion (4).

Despite recent advances in development and regulation of medicines for children, unavoidable factors specific to the care of this age group will always make prescribing for infants and children challenging. These factors (see Figure 12.1) include: • the changes in anatomy and physiology that occur during child development that impact on drug pharmacokinetics and pharmacodynamics. • the general lack of research on drug safety and efficacy in children due to practical and ethical reasons • the need to individualise drug dosage based on parameters such as the child’s age, weight or surface area • the limited availability of medicinal products specifically formulated for children • the vagaries of administering medicines to infants and children • the general difficulties of communicating with children • the challenge of diagnosing and recognising adverse reactions in children • the higher risk for medication error in paediatrics • the frequency of off-label prescribing in paediatrics and associated medicolegal issues, and • recognition that treatment of infants and children involves managing their parents and/or carers as well.

Managing oral pain is a daily task for dental practitioners. Understanding the type of pain, accurately diagnosing the cause and being able to choose the most appropriate drug regimen (if required) is a fundamental skill for all dentists. This chapter describes the medicines commonly used for pain management in dentistry, their mechanism of action, appropriate doses, adverse effects, common drug interactions and their place in therapy.

Dental practitioners are often faced with questions about the safety of dental interventions during pregnancy and breastfeeding. Questions often focus on the safety of the drugs involved such as local anaesthetics, sedatives, analgesics fluoride and antibiotics. Despite the general wisdom that it is best to avoid all drugs during pregnancy and lactation, situations do arise where drug treatment is unavoidable. Therefore, it is necessary that dental professionals competently address these queries with up-to-date, accurate and evidence-based advice or appropriately referral to expert resources. This chapter addresses the common areas of concern for pregnant and breastfeeding women relating to drugs used in dental practice.

Antithrombotic drugs are those used to slow down blood clot formation, including antiplatelet agents and anticoagulants. Dentists commonly encounter patients who are on antithrombotic drugs, as these drugs are used to manage common conditions. For example, the direct oral anticoagulant drugs (DOACs) are frequently prescribed for management of atrial fibrillation, which affects approximately 5% of the Australian population aged 55 and over (1). As a result, the DOACs were within the top 100 drugs dispensed on the PBS in 2018 in Australia (2). Increased risk of oral bleeding is thus a common complication dentists may have to manage. The risk of post-extraction bleeding is increased three-fold in patients taking anticoagulants compared with those not taking these drugs (3, 4). Understanding the principles of haemostasis, how to balance the risk of bleeding against the risk of clotting, and how to manage these patients is thus an integral part of dentistry.

Medical emergencies occur rarely in dental practice. When they do occur, however, they can be both dangerous for the patient and unnerving for the clinician. If these events have been planned for, staff will be adequately trained, the correct medications on hand and their method of use easily recalled, so these rare and disturbing events can be managed with good outcomes. It has been reported that only one resuscitation event occurs for every 250 years of dental practice (1). Although this may seem rare, when it does occur, the event can be life threatening. Therefore, staff training in cardiopulmonary resuscitation (CPR) with regular updates is mandatory. Previous studies have reported very high uptake of CPR training, yet about 20% of dentists felt inadequately prepared and were less likely to have the necessary drugs and equipment in their practice (2). The single most important factor for prevention of medical emergencies in dental practice is the taking of a thorough medical history for each patient.

Dental fear and phobia are common with a prevalence of around 1 in 6 Australian adults (1). Fear of dental care can lead to significant stress and avoidance resulting in neglect and deterioration of oral health (2). The aim of anxiolysis is to improve patient comfort in order to complete dental examination, investigations and procedures (3). This chapter will focus on the pharmacological measures used for anxiolysis in community dentistry.